Over 3,000 bridges in the UK are unable to support the heaviest lorries, costing the government an estimated £3.9bn ($4.7bn) to clear the backlog of necessary construction work.

Councils are currently spending just an eighth of that — an estimated £447m annually to maintain their entire bridge stock.

About 3,203 council-maintained bridges are not suitable for 44 tonne vehicles, according to a study by the RAC Foundation, a transport policy and research organisation.

The maximum permitted weight of lorries was increased in February 2001 to 44 tonnes.

Devon County Council in the south-west of the country has the highest number of bridges — 249 — which are not sturdy enough to support all heavy goods vehicles (HGVs), followed by Somerset with 210 and Essex with 160.

Local councils currently have plans to repair just 416 of 2,512 bridges requiring attention nationally, blaming limited funding and a lack of skills.

In September, a Grade 1 listed bridge in Marlow, Buckinghamshire, was closed for months after a haulage company Girteka Logistics’ lorry — 10 times heavier than the bridge’s weight limit — was driven over it.

“In the face of growing traffic volumes and ageing infrastructure the danger is that without an adequate long-term funding settlement we will see more rather than fewer bridges with weight restrictions, with the backlog bill getting bigger all the time,” said Steve Gooding, RAC Foundation director.

In total, roughly 72,000 bridges can be found on the local road network across the UK.